Computing and networking technology have transformed our world. As the amount of information communicated over networks has increased, high speed transmission has become ever more critical. Many high speed data transmission networks rely on optical transceivers and similar devices for facilitating transmission and reception of digital data embodied in the form of optical signals over optical fibers. Optical networks are thus found in a wide variety of high speed applications ranging from as modest as a small Local Area Network (LAN) to as grandiose as the backbone of the Internet.
Typically, data transmission in such networks is implemented by way of an optical transmitter (also referred to as an electro-optic transducer), such as a laser or Light Emitting Diode (LED). The electro-optic transducer emits light when current is passed there through, the intensity of the emitted light being a function of the current magnitude through the transducer. Data reception is generally implemented by way of an optical receiver (also referred to as an optoelectronic transducer), an example of which is a photodiode. The optoelectronic transducer receives light and generates a current, the magnitude of the generated current being a function of the intensity of the received light.
Various other components are also employed by the optical transceiver to aid in the control of the optical transmit and receive components, as well as the processing of various data and other signals. For example, such optical transceivers typically include an electro-optic transducer driver (e.g., referred to as a “laser driver” when used to drive a laser signal) configured to control the operation of the optical transmitter in response to various control inputs. The optical transceiver also generally includes an amplifier (e.g., often referred to as a “post-amplifier”) configured to perform various operations with respect to certain parameters of a data signal received by the optical receiver.
The operation of an optical transceiver is, however, susceptible to its operating environment. One obvious example of an operating environmental influence is Electro-Magnetic Interference (“EMI”). EMI naturally occurs when the operation of one component causes the unwanted propagation of an electromagnetic field. That electromagnetic field may interfere with the functioning of other proximate electronic components, hence the term “electro-magnetic interference”. Since the components inside an optical transceiver are always in close proximity to each other, EMI is a major problem in optical transceivers.
Many of the components in an optical transceiver have a high sensitivity to extraneous analog signals. If these components encounter any EMI, it can lead to distortion and error in the electric or optical signal that the component produces. For example, if the optical transmitter encounters EMI produced by the electro-optic transducer driver, then the optical transmitter may incorporate the EMI signal and transmit an incorrect transmit signal. In addition, the optical transmitter may be damaged by the EMI signals.
EMI can also cause cross talk or unwanted communication between the transmit and receive paths of the optical transceiver. This can result in an incorrect signal being received by the post-amplifier. There may also be cross talk between individual components. In addition, in some cases, EMI can leak back into a component and distort the signal that is being sent. For example, if EMI produced by the electro-optical transducer driver leaked back into the driver, the driver would send an incorrect signal to the optical transmitter.
In many cases, EMI can also cause damage to surrounding circuitry. The EMI signals can often act as radio waves that are transmitted to a wide surrounding area. This can damage other electric circuits that receive the radio waves. This phenomenon is especially problematic in optical transceivers as multiple transceivers are often used together within a single host. EMI from any one of the optical transceivers can damage the other optical transceivers or distort the transmit signals of the other optical transceivers.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced.